1. Field of the Invention
The present invention relates to a method for switching systems, and in particular to a method for switching dual ID systems installed on equipment complying with SEMI (Semiconductor Equipment and Materials Institute) standard E87.
2. Description of the Related Art
Automated identification systems are widely applied in integrated circuit (IC) manufacturing, such as wafer process, mask process, metal damascene process, oxidation process, and so on. The goal of automated identification is to utilize computers to check errors that may occur during the process by automated monitoring. Computers with automated control technology can manage the wafer fab with minimal operator presence, tracking the entire production process of each wafer by identification label. Manual operation can create mistakes monitoring the production process and identifying identification labels, such as incorrect determinations regarding process events, or during heavy loading.
Carriers must be identified during the semiconductor manufacturing process. In the simplest method, a label with carrier ID or bar code thereof is attached, but problems arise if more information must be recorded for the carrier. The carrier can also be identified by an automated identification system in addition to the label. For equipment automation, automatic identification of the carrier is a basic requirement.
In the separate communication connection system, a host utilizes an identification access device (such as Smart Tag Reader/Writer System) to retrieve the identification data of the wafer carrier through a separate wire link, rather than the tool SECS link. Although the separate wire link is suitable for common equipment, some problems remain.
First, the current Smart Tag solution requires special hardware and add-on deployment and maintenance efforts created additional cabling. Second, the architecture does not comply with the single communication connection requirement in SEMI standard E87. All equipment suppliers comply with SEMI standard in implementation of the equipment installation. If manufacturers do not follow the standard, extra costs are incurred when equipment suppliers must modify their original design for equipment compliance. Third, the identification data for wafer carrier is stored in an identification access device (herein Smart Tag) whose battery must be charged periodically. The identification access device will not work if the battery is not charged.
Furthermore, the separate wire link does not comply with the tool SECS link, such that the host connects to the identification access device directly to access the identification data of the wafer carrier.
FIG. 1 is a flowchart showing implementation of a conventional automated identification system with separate wire link.
In step S11, the equipment installation issues a “load complete” message to the host after the wafer carrier reaches the load port of the equipment installation and the load button thereof is activated.
In step S12, the host directly controls the Smart Tag System through a separate wire link and reads the wafer carrier ID from Smart Tag.
In step S13, the host compares the retrieved wafer carrier ID with product ID numbers from a product ID table established in the manufacturing management system. The retrieved wafer carrier ID is checked by intelligent ID verification.
In step S141, the host issues a “proceed with carrier” request to the equipment installation to continue the manufacturing process if the intelligent ID verification is successful.
In step S142, the host issues a “Cancel Carrier At Port” request to the equipment installation to stop the manufacturing process if the intelligent ID verification is unsuccessful.
In the single communication connection system, the identification access device is installed on The equipment installation. The host issues a request to an equipment installation controller residing on The equipment installation through a single wire link complying with tool SECS link to retrieve the identification data from the wafer carrier and control equipment actions. SEMI standard E87 defines specification for Carrier Management (CMS). For the connection of the identification system, E87 defines a “Single Connection Requirement”, by which the automated identification system must be integrated into the equipment installation and the host accesses identification data through the tool SECS link only. All actions related to the equipment installation and automated identification systems are performed through The equipment installation internal controller.
FIG. 2 is a flowchart showing implementation of a conventional automated identification system with single wire link.
In step S21, the equipment installation issues a “load complete” message to the host after the wafer carrier reaches the load port of the equipment installation and the load button thereof is activated.
In step S22, the equipment installation issues an access request through the single wire link to inform the equipment installation controller it will read the wafer carrier ID stored in the identification access device (herein RF Tag). The equipment installation then uses an identification access system (herein RF Tag Reader/Writer System) by internal connection to retrieve the wafer carrier ID from the identification access device (herein RF Tag).
In step S23, the system chooses if the equipment installation has successfully read the wafer carrier ID.
In step S241, the equipment installation sends a message comprising wafer carrier ID to the equipment installation controller if it has successfully read the wafer carrier ID, and the equipment installation informs the host of the transmission.
In step S242, the equipment installation sends a “read fail” message to the equipment installation controller if it has failed to read the wafer carrier ID, and the equipment installation informs the host of the transmission.
In step S25, the host receives the message comprising wafer carrier ID from equipment controller.
In step S26, the host compares the retrieved wafer carrier ID with product ID numbers from a product ID table established in manufacturing management system. The retrieved wafer carrier ID is checked by an intelligent ID verification.
In step S271, the host issues a “proceed with carrier” request to the equipment installation to continue the manufacturing process if the intelligent ID verification is successful.
In step S272, the host issues a “Cancel Carrier At Port” request to the equipment installation to stop the manufacturing process if the intelligent ID verification is unsuccessful.
Nevertheless, environments supporting automated identification systems with separate communication connection can experience extra costs when introducing an automated identification system with single communication connection.